This is incredibly close, at least as of Thursday afternoon when I’m writing this. Betts is at 8.3 fWAR to Acuña’s 8.0, and 8.5 rWAR to Acuña’s 8.2, so he’s ahead in both metrics but by a very small margin. There’s a great argument for both guys, and Acuña’s more likely to win with the appeal and coverage of his 40/70 season, but I’d go with Betts here because of the versatility he’s brought to the Dodgers this year, playing about 40 percent of his innings at second base and obviously providing more offense than the team was going to get from any outside acquisition at the position.
Acuña has a little more playing time than Betts, leading him by 44 plate appearances, with comparable rate stats, but he’s been a lot worse defensively in right field than Betts by any measure. He’s at minus-9 Outs Above Average this year per Statcast, ahead of only Jordan Walker among regular right fielders, while Betts is at minus-1 OAA in 106 games in right. Betts has also played 67 games at second base and been an average defender there, even though he’d barely played the position in his 10 seasons in the majors, and filled in at short for all or part of 16 games, where he was at minus-2 OAA. So Betts is just barely ahead in the two main measures we have for a player’s total value, and did something else — fill in at two positions where the team needed him, despite having limited experience, and played one of them well enough that the Dodgers were able to get by with just a minor addition via trade in Amed Rosario. I get why many people think Acuña should win, but the 40/70 thing is more fun and interesting than it is meaningful beyond the pure value of those homers and steals.
